To determine the biochemical and biophysical mechanisms of the myocardial depression caused by halothane and other anesthetics and project from this the pharmacological means most appropriate for dealing with anesthetic cardial depression occuring during general anesthesia in man. We have recently found that (1) anesthetics decrease the Ca-influx across the plasma membrane of cardiac muscle by changing the affinity of the Ca-carrier, and (2) anesthetics decrease the Ca-content of sarcoplasmic reticulum by enhancing the Ca-triggered Ca release.